Most discussions surrounding haemodynamic monitoring focus on high-risk surgical patients. Yet growing evidence suggests that intraoperative hypotension (IOH) is associated with adverse postoperative outcomes across a much broader range of procedures and patient populations. At the same time, advances in non-invasive monitoring technologies are challenging traditional assumptions about who may benefit from enhanced haemodynamic assessment. Together, these developments are prompting an important question: is there an evidence gap when it comes to haemodynamic monitoring in low and moderate risk surgery?
A High-Risk Technology for High-Risk Patients
Traditionally, advanced haemodynamic monitoring has been reserved for patients undergoing major surgery or those with significant cardiovascular risk factors. Techniques such as invasive arterial pressure monitoring, cardiac output monitoring and goal-directed haemodynamic therapy (GDHT) have largely been studied in populations considered at high risk of perioperative complications.1,2
This approach has been supported by the principle of balancing clinical benefit against invasiveness, cost and resource requirements. Patients undergoing major abdominal, vascular or cardiac surgery are more likely to experience significant haemodynamic instability and therefore have traditionally been the focus of enhanced monitoring strategies.1
Current guidance reflects this position. The European Society of Anaesthesiology and Intensive Care (ESAIC) recommends monitoring stroke volume or cardiac output in patients with a high baseline risk of complications or those undergoing high-risk surgery to assess haemodynamic status and response to interventions.1
However, this creates an important challenge. While many studies focus on high-risk patients, the majority of procedures performed worldwide fall into low and intermediate-risk categories. If haemodynamic instability occurs across all surgical populations, are opportunities being missed to identify and manage it more effectively in these patients?
Growing Awareness of Intraoperative Hypotension
Over the past decade, research has increasingly highlighted the importance of intraoperative hypotension as more than simply a transient physiological event.
Large observational studies have demonstrated associations between hypotension during surgery and adverse postoperative outcomes, including acute kidney injury, myocardial injury and increased mortality.3,4 Importantly, these associations have been identified in broad surgical populations rather than exclusively among high-risk patients.
At the same time, attention has shifted towards understanding how much hypotension is acceptable, how long patients can tolerate reduced blood pressure and whether blood pressure targets should be individualised.
While debate continues regarding the precise definition of IOH, many experts recommend avoiding a mean arterial pressure (MAP) below 65 mmHg where possible. The 2025 ESAIC guidance recommends maintaining MAP above 60 mmHg during surgery and emphasises the importance of identifying and treating the underlying causes of hypotension.1
As awareness of these risks has grown, so too has interest in methods that may support earlier recognition of haemodynamic deterioration.
Variation in Monitoring Practice
Despite increasing recognition of the importance of haemodynamic stability, substantial variation exists in monitoring practice.
Patients undergoing major surgery frequently receive invasive arterial pressure monitoring, providing continuous blood pressure measurement and access to advanced haemodynamic variables. In contrast, patients undergoing low and intermediate-risk procedures are often monitored using intermittent oscillometric blood pressure measurements taken every three to five minutes.1
Although this remains standard practice, significant haemodynamic changes can occur between measurements. Episodes of hypotension may develop and resolve without being fully captured, particularly during induction of anaesthesia or periods of rapid physiological change.
This variation reflects an important tension within perioperative care. If hypotension is increasingly recognised as an independent risk factor for adverse outcomes, should access to continuous haemodynamic information remain largely restricted to higher-risk settings?
Resource Considerations and Clinical Practicality
Historically, one of the main barriers to broader haemodynamic monitoring has been practicality.
Advanced monitoring systems have often relied on arterial cannulation or other invasive techniques, requiring additional equipment, expertise and procedural time. For many routine surgical procedures, this level of monitoring has not been considered proportionate to the perceived risk.1,2
Healthcare organisations must also balance patient benefit with efficient use of resources. Routine invasive monitoring for all surgical patients would be difficult to justify clinically and economically.
Consequently, clinicians have traditionally relied on risk stratification when determining which patients require enhanced monitoring. However, risk does not exist in discrete categories. Many patients classified as low or moderate risk may still experience hypotensive episodes, particularly following induction of anaesthesia, during positioning changes or as a result of surgical fluid shifts.
This has created growing interest in monitoring technologies that can provide greater physiological insight without the disadvantages associated with invasive techniques.
How Non-Invasive Technologies Are Changing the Conversation
Recent developments in non-invasive haemodynamic monitoring are reshaping discussions around perioperative assessment.
Continuous non-invasive systems can now provide real-time arterial pressure trends and, in some cases, additional haemodynamic information without requiring an arterial catheter. As these technologies become more accessible, they may help reduce some of the traditional barriers that have limited enhanced monitoring to high-acuity environments.5
By providing ongoing haemodynamic information, these technologies may support earlier recognition of physiological deterioration and enable more timely clinical intervention. However, patients who require escalation of care, vasopressor support, frequent arterial blood sampling, or more detailed haemodynamic assessment may still require arterial catheterisation as part of a comprehensive perioperative management strategy.1
Reflecting this shift, the 2025 ESAIC statement suggests considering continuous non-invasive arterial pressure monitoring as an alternative to intermittent oscillometric monitoring in low-risk and intermediate-risk patients who do not otherwise require invasive arterial pressure monitoring.1
The conversation is no longer centred solely on whether every patient requires an arterial line. Instead, the focus is increasingly on whether broader access to continuous physiological information could support earlier recognition of instability and more informed clinical decision-making.
This represents a significant change in thinking. Improved monitoring does not necessarily mean more invasive monitoring. Rather, it enables clinicians to match the level of monitoring to the patient’s physiological status, while retaining the option to escalate to invasive monitoring when clinically indicated
What Does the Evidence Tell Us?
Despite growing interest, significant gaps in the evidence remain.
Much of the research evaluating advanced haemodynamic monitoring and GDHT has focused on major surgery and higher-risk patient groups. While some systematic reviews have reported reductions in postoperative complications with protocolised haemodynamic management, uncertainty remains regarding how these findings apply to lower-risk populations.2,6
Recent expert consensus statements have also highlighted the need for individualised haemodynamic management rather than universal protocols. Future research is expected to focus increasingly on patient-specific haemodynamic targets, technology-assisted decision-making and the role of emerging monitoring platforms.2
As a result, the key question may not be whether enhanced haemodynamic monitoring has value, but rather identifying which patients are most likely to benefit and determining how monitoring data should be incorporated into routine perioperative care.
Looking Ahead
The conversation around haemodynamic monitoring is changing.
Rather than being driven solely by increasingly complex patient populations, interest is being fuelled by a growing understanding that intraoperative hypotension matters across a much wider range of surgical patients than previously recognised. At the same time, advances in non-invasive technology are making continuous haemodynamic assessment more accessible than ever before.^1,3,5
Future research will help clarify whether enhanced monitoring can improve outcomes in low and moderate risk surgery and define the patient groups most likely to benefit. However, the direction of travel is becoming increasingly clear.
As barriers to monitoring continue to fall, clinicians may gain access to haemodynamic information that was once available only in high-acuity settings. The result could be a more personalised approach to perioperative care, where monitoring strategies are guided not only by traditional risk categories but also by the need to identify and respond to haemodynamic instability before it impacts patient outcomes.
References
- Saugel B, Buhre W, Chew MS, Cholley B, Coburn M, Cohen B, et al. Intra-operative haemodynamic monitoring and management of adults having noncardiac surgery: A statement from the European Society of Anaesthesiology and Intensive Care. Eur J Anaesthesiol. 2025;42(6):543-556.
- Edwards MR, Kunst G, Forni LG, Chappell D, Miller TE, POQI-11 Group. Perioperative Quality Initiative consensus statement on goal-directed haemodynamic therapy. Br J Anaesth. 2025;135(3):547-560.
- Walsh M, Devereaux PJ, Garg AX, Kurz A, Turan A, Rodseth RN, et al. Relationship between intraoperative mean arterial pressure and clinical outcomes after noncardiac surgery. Anesthesiology. 2013;119(3):507-515.
- Karamchandani K, Dave S, Hoffmann U, Khanna AK, Saugel B. Intraoperative arterial pressure management: knowns and unknowns. Br J Anaesth. 2023;131(3):445-451.
- Saugel B, Hoppe P, Nicklas JY. Continuous noninvasive haemodynamic monitoring in perioperative and intensive care medicine. Br J Anaesth. 2020;125(1):25-37.
- Jalalzadeh H, Hulskes RH, Weenink RP, Wolfhagen N, van Dusseldorp I, Schaad RR, et al. Systematic review and meta-analysis of goal-directed haemodynamic therapy algorithms during surgery for the prevention of surgical site infection. EClinicalMedicine.
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